Platen clutch



Y y I Y 1,614,548 Jan' 18,1927' c. GABRIELsoN PLATEN CLUTCH Filed Jan.26. 1925 dll Patented Jan. 18, 1927.

UNITED STATES PATENT OFFICE.

CARL GABRIELSON, OF SYRACUSE, NEW YORK, ASSIGNOR T0 L. C. SMITH & BROS.TYPEWRITER, INC., OF SYRACUSE7 NEIV YORK, A CORPORATION OF NEW YORK.

i rLA'rnN CLUTCH.

Application led January This invention relates to that typel of clutchwhich normally locks the line-spaceratchet wheel to the platen of atypewriter, but which permits `the platen to be released so that it maybe turned while the ratchet wheel is stationary for irregular spacingand other purposes.' The present application discloses an improvement onmy previous Patenty No. 1,393,277, dated Oct. 11, 1921. y

In the accompanying` drawings and following specification there isdisclosed by wayof example, only, a single embodiment of the presentinvention with the understanding however that various changes may bemade by one skilled in the art in the material, size, form, proportionand arrangement of the various parts without departing` from the spiritor scope of the attached claims.

In said drawings:

Fig. 1 is a longitudinal central section through the clutch end of atypewriter platen;

Fig. 2 is an end view of a clutch mechanism with the cover plate removedand the shaft shown in section;

Fig. 3 is a longitudinal central section at right angles to that shownin Figure 1 through the clutch release mechanism; and

Fig. 4 is a perspective view of one of they locking members.

The clutch mechanism on the platen of a typewriter is subject toconsiderable usage and it has been found at times that such a clutchfails to operate satisfactorily, sometimes failing to hold and at othertimes failing to completely release. This condition may result inimproper spacing of the lines making it difficult to obtain neattypewritten pages. The present invention overcomes the diiiiculty bysoarrangingthe locking parts of the clutch that they are always in thesame relative relation to each other and cannot cause jamming or failureto hold.

In the above `mentioned patent the clutch mechanism and its associatedparts is quite fully described and in the present application it isbelieved to be only necessary to generally mention the various parts.The platen roll may be formed of wood or any other suitable material andprovided with the sheath 11 formed of hard rubber er the like. Theplaten adapted to be 26, 192'5. Serial No. 4,916.

supported in the carriage of the typewriter in any well known manner andis provided at 12 with a large axial bore having a smaller extension 13at the bottom thereof to provide an intermediate shoulder 14. Y At itsclutch end the platen Ais provided with a circular plate 15 having a hub16 which fits and ext-ends into the bore 12, the plate 15 being attachedto the wooden core by screws or any other suitable holding means notshown. The plate 15 has an annular shoulder 17 formed by the flange 18on the outer side of its hub and upon this shoulder is mounted the innerring or race member 19 which is similar to the inner race member of aroller bearing and is provided with the cylindrical surface 20 and theinner end flange 21 radiating therefrom. On the cylindrical surface bearthe locking members 22 which will be later described in detail, andadapted to rotate upon their outer surfaces is the outer race or ringmember 23 carrying the usual ratchet 24 which cooperates with the springholding pawlor roller 25 and with a line-space feed-pawl not shown. Theinner end of the ring or race 23 abuts against the flange 21 and isprevented from moving outwardly by the concentric cap 26 which isrigidly connected both to the inner race member 19 and the end plate 15,such as by suitable screws 27.

As described in the above mentioned patent, the clutch is adapted to beoperated by a rocking device having arms 28 which are actuated by a camblock 29 slidably mounted upon the shaft 30 supported concentricallywith the platen in the cap 26 and washer 14 abutting against theshoulder 14. The cam block is normally urged toward the clutch by thecoil spring 31 surrounding the shaft 30 and abutting at its left endagainst the stop nut 32. The eam 4block 29 is adapted to be moved to theleft by means of a rod 33 slidably mounted within a groove in the shaft30 and having its outer end extending beyond this shaft to be engaged bythe cap 34 and pressed inwardly in-respect to the shaft to move the camblock against the spring and release the operating arms 28 to theposition shown in Figure 1. If desired means may be provided for lockingthe cap 34 in the released position such as the bayonet lock shown inFigure 3, but since this forms no part of the present invention, it willnot be described.

The clutch operatesl tohlock the races 19 and 23 together by jamming,`the locking members 22 between the two rings or races 19 and 23 whichare ordinarily tree to rotate with'respeet to each other, the outer ringriding on the surfaces of the locking ineinbers 22. These lockinglmembers are janinned or crowded against each other and thus moveoutwardly to engage the inner surfaces oli' the outer rae-e 23, byymeans ot the liattened faces 35 on the stu-d 36 which is carried by thecollar 37 supporting theclutch actuating.;` arms 28. "lhis collar 37 isprovided with an opening' to allow it to pass Vfreely over the shaft 30.

It is maintained in position ai'idsupported tor rotation about an axistransverse to the shaft 30 and through the center of the stud 36 bymeans o tthe projecting reduced end 33 ot the screw 39 radially mountedin vthe inner race 19. rllhis end 33 fits into a hole in the collar andforms a` journal therefor. @the stud 3G has a bearing in the circularhole 110 in this race diametrically opposite from the screw 39 so vthatit will be eyident that the clutch operating larms 2S are Yfree to movewithin the limitsdelineel by the cam lock 2 9 about van axis through thestud 36 and the. projecties 38# The'head "of the Vscrew projects intothe mailer Sres@ beieee the asfs 19 and 28 do the'tlattened faces 35lthe stud 3G the remaining po rions of this annular space being' withthe "locling members sfo tliat'wlien the flattened faces 35 'are rotatedfrom rthe position shown in Figure lito a position where they form anangle to the axes of .the looking` members7 they' Will jammed in .theSpace 'bewees the annular race members 19 and 23 and betweenlthe headthe screw 39 and the iat Ifaces '35 o'l' the stud 36.' They ywill thusmove -radially outward to Contact with the inner faQ- Q Of the race 23and lock it to the race 19. This action is assisted by the fact that thelooking members 22, cannot move circumferentially Ain respect to therace 19 owing to the sc ren7 head 39 egtending into the annular spacebetween the two races.

` The most important feature of this invention consists in the'shape'ofthe locking members The amount of'inovement of the wedging stud 36 Iisquite limitedand it ls necessary therefore lthat the aggregate lengthmeasured in an arc through each group oi" locking .members yshall beslightly less than the distance measured on the lsame arc from the headof the Screw to the flat iace ol the stud 36 when the clutch is inieleased position shown in Figure 1, and Slightly greater than thislength when the operating arms 28 are lifted bythe cam faces 29r towedge these members between'the two races. It they are formed ascylinders it will be :found` almost impossible to make each cylindertruly round and it is tlie'rel'orc obvious that at suoli times thesecylindersl may be so grouped that most of their short diameters all lieupon the above mentioned are, the clutch -may slip and il a largeninnber of cylinders are so positioned, that their longer diameters lieon this are then the clutch may 'fail to release. To overcome thesedi'tlicnlti'es the present invention contemplates forming the lockingmembers ,as short cylinders each having a liatteued yside or face 43 thediameters ot' the .cylinders being` greater than the radial distancebetween the vtwo races and the diametrical distance 'from the center olfa iiattened side to the opposite surface of the are being' just slightlyler-,s than this radial distance be" tween `the tivo races. The lockingmembers 22 are then positioned so that their flattened faces L13 all lieagainst the vinner race and thus the same elements of the surfacesthereotmust always abut the adjacent locking members and when oncee theinitial adjustment has been made, no possible change can take place inthe aggregate length vof each roup measured'along the are previo'usly're- `erred to,

The end members of each group are cylinders having a. diameter onlylslightly less than the distance between the two race meinbers and theseend menibers l14 Yeach have a Hattened 'lace A12/to abutaftljai'nst'eitherY the head oitthe screw 39 ontheflatiacesS 'on lLilieend ot the stud 36. By providingI end members with various Widthflattened Afaces the initialY adjustment of the cluteh'can'be verycarefully madeV after whiclithe're will be n o vchange and [a positivelocking and a total disengagement `will resultwhen'the ram block isactuatedy as above described. lt will therefore.beseeii that theessential l'eature of this invention coiisists'in the provision oilockingr members' non-circular in cross section in order thatthey'mayalways reain their ysame relative position in respect to eachother. 'Y

Having thus described the invention what is claimed as newaud desired tobe secured by `Letters lateiit is: l 1` ln a clutch mechanism, incombination, an inner race member and an louterV race member forming anyannular channel, lock.- ing membe in said channel, means to 'eteitcircumferential pressure o n said lockingv members to crowd them againstsaid outer race member, said locking members being constrained to alwaysengage adjacent members at the 4same place.l i

'2. ln a clutch mechanism in combination, an inner racev 1n e` 1nber,locking yinelmliers arranged around the rperiphery (thereof, an outerrace member normally 'rotatable around said locking menibers and meansto crowd said locking` members into engagement with said outer racemember tolo'clr Sie .l Ut) lit? 1t to the inner race member, saidlocking members lhaving one axis longer than the distance between saidrace members.

In a clutch mechanism, in combination, an inner race member, lockingmembers arranged around the periphery thereof, an outer race memberrotatable on said locking members, means to lock said races togethercomprising a part extending between said races to crowd said lockingmembers apart, said locking members being constrained against rotationabout their own axes at all times.

4. In a clutch mechanism, in combination, an inner race member, lockingmembers arranged around the periphery thereof, an outer race memberrotatable on said locking members, means to lock said races togethercomprising a part extending between said races to crowd said lockingmembers apart, each of said locking members having a face adapted toengage a race member to prevent relative rotation of the locking memberat all times so that each locking member will always retain its samerelative position in respect to the remaining locking members.

5. The combination with a typewriter platen of a head thereon having araceway,

locking members in said raceway, a ratchet ring mounted on said lockingmembers and means for crowding the locking members to lock the ratchetring to the platen, said means including an abutment extending into theraceway at one point thereof and a device extending into the raceway atanother point thereof and means for turning said device to crowd thelocking members against the abutment and radially against the ratchetring to lock it to said platen, said locking members being cylindershaving a flattened side resting on said inner race member.

In testimony whereof I hereunto ati-ix my signature.

GAR-L GABRIELSON.

